The present invention relates generally to an elevator system and, in particular, to a group control for elevators with double cars for the immediate allocation of target calls.
A control for an elevator group with double cars is shown in the Swiss patent document CH-PS 529 054 in which the double cars are constructed in such a manner that two adjacent floors can be served at the same time. In this case, the filling of a building can be achieved in the shortest possible time with approximately uniform occupation of the double cars. The passengers traveling to even-numbered upper floors board the upper car and those traveling to the odd-numbered upper floors board the lower car on the ground floor, wherein the car call transmitters are blocked each time for the floors not associated with the car. After departure from the ground floor, as soon as the car stops in response to a floor call, the blocking is canceled so that the boarding passenger can travel to any desired floor.
Elevators of the above-described kind can convey twice as many passengers during each trip as elevators with single cars. Since less stopping has to be done, the same number of floors can be served in a shorter time so that the conveying performance is increased appreciably. However, it can occur with this control that passengers, who do not observe the division of the even-numbered and the odd-numbered floors over the upper and lower cars respectively, do not reach the desired floor and must alight at a different one. It must also be regarded as disadvantageous that the constraint to use the right car, which is exerted on the boarding passengers at the main stopping floor, exists not only during the relatively short time of the peak traffic, but also during the remaining time.
Another control, which is shown in the European patent document EP-A 0 301 178, is used for elevators with single or double cars and has call registering devices with keys for the entry of calls for desired target floors located on the floors and no call buttons are provided in the elevator cars. At the main stopping floor, call registering devices with keys for even-numbered target floors are located at the access for the upper cars of the double cars while the access for the lower cars of the double cars has located there call registering devices with keys for odd-numbered target floors. It is proposed in a further example of the embodiment to use call registering devices with decade keyboards, wherein the keys for the odd-numbered target floors at the upper access and the keys for the even-numbered target floors at the lower access are made ineffective. Even in the case of this control equipment, a passenger must consider exactly which access he has to use in order to reach the desired travel target. On use of a wrong access, however, the error can still be noticed before boarding the car so that the correct travel target can be reached through a change to the proper access.
A group control for single cars is shown in the European patent document EP-A 0 356 731 which applies the shortest waiting time of all passengers as the criterion for the allocation of the cars to the entered calls. In this control, the travel targets can likewise be entered at the floors by the call registering and indicating
devices shown in the European patent document EP-A 0 320 583. Immediately after the registration and transfer of a call into a call memory divided according to input and target floors, a computer in the form of a microprocessor computes a sum called operating costs for each car from data specific to the elevator, which sum corresponds to the waiting time which would arise for the passengers in the serving of the call. The operating costs are transferred immediately after the computation into a costs register and subsequently immediately compared with the operating costs of the other elevators by means of a comparison device. In this case, an allocation instruction is stored in an allocation memory of that car which has the lowest operating costs. Immediately after the allocation of a car to the call has taken place in this manner, the elevator concerned and its position are indicated in an indicating field of the actuated call registering and indicating device so that the passenger can move in good time to the associated shaft door.